Resonator with retention ribs

ABSTRACT

A resonator includes an inner perforated tube, an outer shell, and a plurality of annular ribs extending radially therebetween and defining resonant chambers. Progressive stepping of ribs and grooves enables axial insertion assembly with minimal cost. The need for welding or secondary bonding operations is eliminated.

BACKGROUND AND SUMMARY

The invention relates to resonators, including intake resonator silencers for internal combustion engines.

Intake resonators are known in the art, and are constructed from various materials including metal and/or plastic. Blow molded bottle style resonators are known and fitted under the hood of automobiles, trucks, agricultural and construction vehicles, marine vehicles, and recreational vehicles. Various constructions employ hollow structures made of plastic which are bonded together using vibration or sonic welding or other types of friction welding. Other types of structures have additional elastomer seals, adding expense. Other structures of reduced cost are not gas tight, and therefore lack in performance.

The present invention provides a simple, cost effective resonator without performance trade-off.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective assembly view of a resonator in accordance with the invention.

FIG. 2 is a cut-away view of the assembly of FIG. 1.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1.

FIG. 4 is a perspective view partially cut-away of the inner perforated tube of FIGS. 1-3.

DETAILED DESCRIPTION

FIG. 1 shows a resonator 10 extending axially along an axis 12 between distally opposite axial ends 14 and 16 providing an inlet and an outlet, respectively, for example for receiving intake combustion air at inlet 14 and delivering the combustion air from outlet 16 to an internal combustion engine (not shown). Resonator 10 has an inner perforated tube 18, FIGS. 2-4, an outer shell 20, and at least one and preferably two or more annular ribs such as 22, 24 spaced axially between inlet 14 and outlet 16 and extending radially between inner perforated tube 18 and outer shell 20. In preferred form, inner tube 18 is an injection molded plastic member, and outer shell 20 is a blow molded or rotationally molded plastic member, and the ribs extend integrally radially outwardly from inner tube 18. The ribs define a first resonant chamber 26 between inner perforated tube 18 and outer shell 20 axially upstream of rib 22, a second resonant chamber 28 between inner perforated tube 18 and outer shell 20 axially downstream of rib 22 and axially upstream of rib 24, and a third resonant chamber 30 between inner perforated tube 18 and outer shell 20 axially downstream of rib 24. Inner perforated tube 18 has a first set of perforations 32 radially aligned with resonant chamber 26, a second set of perforations 34 radially aligned with resonant chamber 28, and a third set of perforations 36 radially aligned with resonant chamber 30. The resonator attenuates sound waves in gas flow entering the resonator at inlet 14 and exiting the resonator at outlet 16. The gas flows axially through the hollow interior of perforated tube 18 and communicates with resonant chambers 26, 28, 30 through respective sets of perforations 32, 34, 36.

The set of perforations 32 are the only inlet to and the only exit from resonant chamber 26, such that gas flow in the hollow interior of inner perforated tube 18 can enter resonant chamber 26 only through the set of perforations 32, and can exit resonant chamber 26 only through the set of perforations 32. The second set of perforations 34 are the only inlet to and the only exit from resonant chamber 28, such that gas flow in inner perforated tube 18 can enter resonant chamber 28 only through the set of perforations 34, and can exit resonant chamber 28 only through the set of perforations 34. The third set of perforations 36 are the only inlet to and the only exit from resonant chamber 30, such that gas flow in inner perforated tube 18 can enter resonant chamber 30 only through the set of perforations 36, and can exit resonant chamber only through the set of perforations 36. The upstream inlet ends 38 and 40 of inner tube 18 and outer shell 20, respectively, engage each other in tight fit flush relation, such that gas flow enters resonator 10 only through the hollow interior of inner tube 18. The downstream outlet ends 42 and 44 of inner tube 18 and outer shell 20, respectively, engage each other in tight fit flush relation, such that gas flow exits the resonator at outlet 16 only through the hollow interior of inner perforated tube 18.

Rib 22 extends radially outwardly from inner perforated tube 18 and has an outer tip 46. Outer shell 20 has an inner surface 48 facing radially inwardly toward inner perforated tube 18 and has a sealing engagement surface 50, FIG. 3, engaging outer tip 46 of rib 22 in radially engaged tight fit relation such that inner perforated tube 18 is axially insertable (downwardly in FIGS. 1-3) into outer shell 20 and held in radially engaged relation therein, to be further described. Rib 24 extends radially outwardly from inner perforated tube 18 and has an outer tip 52. Outer shell 20 has an inner surface 54 facing radially inwardly toward inner perforated tube 18 and has a sealing engagement surface 56 engaging outer tip 52 of rib 24 in radially engaged tight fit relation such that inner perforated tube 18 is axially insertable (downwardly in FIGS. 1-3) into outer shell 20 and held in radially engaged relation therein, to be further described. Outer tip 46 of rib 22 engages surface 50 in sealing relation, isolating resonant chamber 26 from resonant chamber 28. Outer tip 52 of rib 24 engages surface 56 in sealing relation, isolating resonant chamber 28 from resonant chamber 30.

Resonant chamber 26 is sealed at its upstream end by the flush tight fit engagement of ends 38 and 40 of inner tube 18 and outer shell 20, respectively, and is sealed at its downstream end by the engagement of rib tip 46 and surface 50. Resonant chamber 28 is sealed at its upstream end by the engagement of rib tip 46 and surface 50, and is sealed at its downstream end by the engagement of rib tip 52 and surface 56. Resonant chamber 30 is sealed at its upstream end by the engagement of rib tip 52 and surface 56, and is sealed at its downstream end by the flush fit tight engagement of downstream ends 42 and 44 of inner tube 18 and outer shell 20, respectively.

Each of sealing engagement surfaces 50 and 56 is a detent engaging the respective outer tip 46 and 50 of the respective rib 22 and 24 in snap-fit relation upon the noted axial insertion. Outer shell 20 has an outer surface 58 with an annular groove 60 recessed radially inwardly toward inner perforated tube 18 and providing the noted sealing engagement surface 50 on inner surface 48. Outer shell 20 has an outer surface 62 with an annular groove 64 recessed radially inwardly toward inner perforated tube 18 and providing sealing engagement surface 56 on inner surface 54.

Inner perforated tube 18 is a two-piece member having first and second pieces 66 and 68 abutting each other at first and second axially extending abutment lines 70 and 72 in assembled condition in outer shell 20. Pieces 66 and 68 are preferably held in assembled condition in outer shell 20 solely by outer shell 20, without bonding or welding of pieces 66 and 68 to each other. Further preferably, pieces 66 and 68 are identical, which enables the use of a single tool for forming same, to reduce tooling cost. One axially extending edge of each piece, such as edge 74, FIG. 4, along abutment line 70, is concave as shown at 76, while the other axially extending edge 78 at abutment line 72 is convex or bulged as shown at 80 to mate in the concave edge of the other piece. Other types of interlocking engagement of pieces 66 and 68 may be used to provide proper alignment of the pieces during axial insertion into outer shell 20, whereafter the pieces are held in assembled condition by engagement of ribs 22 and 24 with respective detents 50 and 56.

Inner perforated tube 18 and outer shell 20 have the noted upstream axial ends 38 and 40 mating at an upstream joint 82, FIG. 3, blocking gas flow therepast at inlet 14 such that gas flow at inlet 14 can only flow into the hollow interior of perforated inner tube 18 and not into the space between inner tube 18 and outer shell 20. Inner perforated tube 18 and outer shell 20 have the noted downstream axial ends 42 and 44 mating at a downstream joint 84 blocking gas flow and sound therepast at outlet 16 such that gas flow at outlet 16 can only flow from the hollow interior of inner perforated tube 18 and not from the space between inner tube 18 and outer shell 20. The upstream axial end of inner perforated tube 18 has first and second different diameter portions 86 and 88, FIG. 3, and a transition portion 90 therebetween. The diameter of portion 86 is larger than the diameter of portion 88 and mates with outer shell 20. Transition portion 90 extends radially inwardly from first diameter portion 86 to second diameter portion 88. The downstream axial end of outer shell 20 has third and fourth different diameter portions 92 and 94 and a transition portion 96 therebetween. The diameter of portion 94 is smaller than the diameter of portion 92 and mates with inner perforated tube 18. Transition portion 96 extends radially inwardly from third diameter portion 92 to fourth diameter portion 94.

The number of ribs 22, 24 equals N, the number of grooves 60, 64 equals N, and in preferred form, N is greater than or equal to 2, and the number of resonant chambers 26, 28, 30 equals N+1, and the number of sets of perforations 32, 34, 36 equals N+1. The ribs 22, 24 have a radial height between inner perforated tube 18 and outer shell 20, which radial height progressively increases from rib to rib. As seen in FIGS. 3 and 4, the radial height of rib 22 is greater than the radial height of rib 24. The ribs extend radially outwardly from inner perforated tube 18. Outer shell 20 has the noted plurality of annular grooves 60, 64 axially spaced from each other and serially axially spaced between inlet 14 and outlet 16 and radially aligned with and engaging respective ribs 22 and 24. The grooves have a radial depth progressively increasing from groove to groove in inverse relation to the progression of the progressively increasing height of the ribs. As seen in FIGS. 2 and 3, the radial depth of groove 64 is greater than the radial depth of groove 60. The shortest radial height rib 24 engages the deepest radial depth groove 64. The tallest radial height rib 22 engages the shallowest radial depth groove 60. This construction facilitates axial insertion of inner perforated tube 18 into outer shell 20, and enables such axial insertion without a draft on inner tube 18.

In the present method for assembling a resonator, the inner perforated tube 18 is axially inserted into outer shell 20 (downwardly in FIGS. 1-3). First and second pieces 66 and 68 are abutted at axially extending abutment lines 70 and 72 to a pre-assembled condition. The first and second pieces 66 and 68 in the pre-assembled condition are inserted axially into outer shell 20 such that pieces 66 and 68 are held in assembled condition in outer shell 20, preferably solely by outer shell 20, without bonding or welding of pieces 66 and 68 to each other. Radial retention force is provided by the snap-fit detent engagement of ribs 22, 24 and detent sealing engagement surfaces 50, 56, respectively. The noted progressive stepping of the ribs and grooves facilitates the noted axial insertion, including without drafting.

It is recognized that various equivalents, alternatives and modifications are possible within the scope of the appended claims. 

1. A resonator extending axially along an axis between distally opposite axial ends providing an inlet and an outlet, said resonator comprising an inner perforated tube, an outer shell, and at least one annular rib spaced axially between said inlet and said outlet and extending radially between said inner perforated tube and said outer shell and defining a first resonant chamber between said inner perforated tube and said outer shell axially upstream of said rib, and defining a second resonant chamber between said inner perforated tube and said outer shell axially downstream of said rib, said inner perforated tube having a first set of perforations radially aligned with said first resonant chamber, said inner perforated tube having a second set of perforations radially aligned with said second resonant chamber.
 2. The resonator according to claim 1 wherein said resonator attenuates sound waves in gas flow entering said resonator at said inlet and exiting said resonator at said outlet, the gas flowing axially through said inner perforated tube and communicating with said first and second resonant chambers through said first and second sets of perforations, respectively.
 3. The resonator according to claim 2 wherein said rib isolates said first resonant chamber from said second resonant chamber.
 4. The resonator according to claim 2 wherein said rib seals said first resonant chamber from said second resonant chamber.
 5. The resonator according to claim 2 wherein: said first set of perforations are the only inlet to and the only exit from said first resonant chamber, such that gas flow in said inner perforated tube can enter said first resonant chamber only through said first set of perforations, and can exit said first resonant chamber only through said first set of perforations; said second set of perforations are the only inlet to and the only exit from said second resonant chamber, such that gas flow in said inner perforated tube can enter said second resonant chamber only through said second set of perforations, and can exit said second resonant chamber only through said second set of perforations.
 6. The resonator according to claim 5 wherein said gas flow enters said resonator at said inlet only through said inner perforated tube, and said gas flow exits said resonator at said outlet only through said inner perforated tube.
 7. The resonator according to claim 2 wherein said rib extends radially outwardly from said inner perforated tube and has an outer tip, and said outer shell has an inner surface facing radially inwardly toward said inner perforated tube and has an engagement surface engaging said outer tip of said rib in radially engaged relation such that said inner perforated tube is axially insertable into said outer shell and held in radially engaged relation therein.
 8. The resonator according to claim 7 wherein said outer tip of said rib engages said engagement surface in sealing relation isolating said first resonant chamber from said second resonant chamber.
 9. The resonator according to claim 7 wherein said engagement surface comprises a detent engaging said outer tip of said rib in snap-fit relation.
 10. The resonator according to claim 7 wherein said outer shell has an outer surface with an annular groove recessed radially inwardly toward said inner perforated tube and providing said engagement surface.
 11. The resonator according to claim 2 wherein said inner perforated tube and said outer shell have upstream axial ends mating at an upstream joint blocking gas flow therepast at said inlet such that gas flow at said inlet can only flow into said perforated inner tube and not into the space between said inner perforated tube and said outer shell, and wherein said inner perforated tube and said outer shell have downstream axial ends mating at a downstream joint blocking gas flow therepast at said outlet such that gas flow at said outlet can only flow from said perforated inner tube and not from the space between said inner perforated tube and said outer shell.
 12. The resonator according to claim 11 wherein: one of said upstream axial ends of said inner perforated tube and said outer shell has first and second different diameter portions and a first transition portion therebetween, said first diameter portion being larger than said second diameter portion and mating with the other of said upstream axial ends of said inner perforated tube and said outer shell, said first transition portion extending radially inwardly from said first diameter portion to said second diameter portion; one of said downstream axial ends of said inner perforated tube and said outer shell has third and fourth different diameter portions and a second transition portion therebetween, said third diameter portion being larger than said fourth diameter portion and mating with the other of said downstream axial ends of said inner perforated tube and said outer shell, said second transition portion extending radially inwardly from said third diameter portion to said fourth diameter portion.
 13. The resonator according to claim 11 wherein: said upstream axial end of said inner perforated tube has first and second different diameter portions and a first transition portion therebetween, said first diameter portion being larger than said second diameter portion and mating with said outer shell, said first transition portion extending radially inwardly from said first diameter portion to said second diameter portion; said downstream axial end of said outer shell has third and fourth different diameter portions and a second transition portion therebetween, said fourth diameter portion being smaller than said third diameter portion and mating with said inner perforated tube, said second transition portion extending radially inwardly from said third diameter portion to said fourth diameter portion.
 14. The resonator according to claim 1 wherein said inner perforated tube is a two-piece member having first and second pieces abutting each other at first and second axially extending abutment lines in an assembled condition in said outer shell, and wherein said first and second pieces are held in said assembled condition in said outer shell solely by said outer shell, without bonding or welding of said first and second pieces to each other.
 15. The resonator according to claim 1 wherein said inner perforated tube is a two-piece member having first and second pieces abutting each other at first and second axially extending abutment lines in an assembled condition in said outer shell, said first and second pieces being identical and enabling the use of a single tool for forming same, to reduce tooling cost.
 16. A resonator extending axially along an axis between distally opposite axial ends providing an inlet and an outlet, said resonator comprising an inner perforated tube, an outer shell, and a plurality of annular ribs axially spaced from each other and serially axially spaced between said inlet and said outlet and extending radially between said inner perforated tube and said outer shell and defining a plurality of resonant chambers between said inner perforated tube and said outer shell, said inner perforated tube having a plurality of sets of perforations radially aligned with respective said resonant chambers.
 17. The resonator according to claim 16 wherein the number of said ribs equals N, where N≧2, the number of said resonant chambers equals N+1, and the number of said sets of perforations equals N+1.
 18. The resonator according to claim 16 wherein said ribs have a radial height between said inner perforated tube and said outer shell, and wherein said radial height progressively increases from rib to rib.
 19. The resonator according to claim 18 wherein said ribs extend radially outwardly from said inner perforated tube, said outer shell has a plurality of annular grooves axially spaced from each other and serially axially spaced between said inlet and said outlet and radially aligned with and engaging respective said ribs, and wherein said grooves have a radial depth progressively increasing from groove to groove in inverse relation to the progression of said progressively increasing height of said ribs.
 20. The resonator according to claim 19 wherein the shortest radial height rib engages the deepest radial depth groove, and the tallest radial height rib engages the shallowest radial depth groove.
 21. The resonator according to claim 20 wherein said inner perforated tube is insertable axially into said outer shell, and wherein said progressively increasing radial depth of said grooves in inverse relation to the progression of the progressively increasing height of said ribs facilitates said axial insertion.
 22. The resonator according to claim 19 wherein the number of said ribs equals N, where N≧2, the number of said grooves equals N, the number of said resonant chambers equals N+1, and the number of said sets of perforations equals N+1.
 23. A method for assembling a resonator extending axially along an axis between distally opposite axial ends, namely an inlet and an outlet, comprising providing an inner perforated tube, providing an outer shell, providing at least one annular rib on one of said inner perforated tube and said outer shell, and axially inserting said inner perforated tube into said outer shell.
 24. The method according to claim 23 comprising axially inserting said inner perforated tube into said outer shell such that said rib is spaced axially between said inlet and said outlet and extends radially between said inner perforated tube and said outer shell and defines a first resonant chamber between said inner perforated tube and said outer shell axially upstream of said rib, and defines a second resonant chamber between said inner perforated tube and said outer shell axially downstream of said rib, providing said inner perforated tube with a first set of perforations radially aligned with said first resonant chamber, providing said inner perforated tube with a second set of perforations radially aligned with said second resonant chamber.
 25. The method according to claim 24 comprising providing said rib extending radially outwardly from said inner perforated tube and having an outer tip, providing said outer shell with an inner surface facing radially inwardly toward said inner perforated tube and having an engagement surface, axially inserting said inner perforated tube into said outer shell such that said outer tip of said rib engages said engagement surface in radially engaged relation such that said inner perforated tube and said outer shell are held in radially engaged relation.
 26. The method according to claim 25 comprising engaging said outer tip of said rib and said engagement surface in sealing relation isolating said first resonant chamber from said second resonant chamber.
 27. The method according to claim 25 comprising providing said engagement surface as a detent, and inserting said inner perforated tube into said outer shell such that said outer tip of said rib engages said detent in snap-fit relation.
 28. The method according to claim 25 comprising providing said outer shell with an outer surface having an annular groove recessed radially inwardly toward said inner perforated tube and having an inner surface providing said engagement surface, and comprising inserting said inner perforated tube axially into said outer shell such that said outer tip of said rib engages said engagement surface.
 29. The method according to claim 23 comprising providing said inner perforated tube as a two-piece member having first and second pieces, abutting said first and second pieces at first and second axially extending abutment lines to a pre-assembled condition, inserting said first and second pieces in said pre-assembled condition axially into said outer shell such that said first and second pieces are held in assembled condition in said outer shell solely by said outer shell, without bonding or welding of said first and second pieces to each other.
 30. The method according to claim 23 comprising providing said inner perforated tube as a two-piece member having identical first and second pieces, abutting said first and second pieces to each other at first and second axially extending abutment lines in a pre-assembled condition, axially inserting said first and second pieces in said pre-assembled condition into said outer shell.
 31. The method according to claim 30 comprising forming said first and second identical pieces by the same tool, to reduce tooling cost.
 32. A method for assembling a resonator extending axially along an axis between distally opposite axial ends, namely an inlet and an outlet, comprising providing an inner perforated tube, providing an outer shell, providing a plurality of annular ribs axially spaced from each other and serially axially spaced between said inlet and said outlet for extending radially between said inner perforated tube and said outer shell and defining a plurality of resonant chambers between said inner perforated tube and said outer shell, providing said inner perforated tube with a plurality of sets of perforations to be radially aligned with respective said resonant chambers, and axially inserting said inner perforated tube into said outer shell.
 33. The method according to claim 32 comprising providing N said ribs, where N≧2, providing N+1 said resonant chambers, and providing N+1 said sets of perforations.
 34. The method according to claim 32 comprising providing said ribs with a radial height extending between said inner perforated tube and said outer shell, and progressively increasing said radial height from rib to rib.
 35. The method according to claim 32 comprising providing said ribs extending radially outwardly from said inner perforated tube, providing said outer shell with a plurality of annular grooves axially spaced from each other and serially axially spaced between said inlet and said outlet and radially aligned with and engaging respective said ribs, providing said grooves with a radial depth progressively increasing from groove to groove in inverse relation to the progression of said progressively increasing height of said ribs.
 36. The method according to claim 35 comprising, upon axial insertion of said inner perforated tube into said outer shell: engaging the shortest radial height rib with the deepest radial depth groove; and engaging the tallest radial height rib with the shallowest radial depth groove.
 37. The method according to claim 36 comprising providing said inner perforated tube without a draft, and inserting said inner perforated tube axially into said outer shell without a draft.
 38. The method according to claim 35 comprising providing N said ribs, where N≧2, providing N said grooves, providing N+1 said resonant chambers, and providing N+1 said sets of perforations. 